著者

小松 藤男 小園 善保 小森 英夫 桜井 和寿

出版者

室蘭工業大学

雑誌

室蘭工業大学研究報告 = Memoirs of the Muroran Institute of Technology (ISSN:05802393)

巻号頁・発行日

vol.3, no.3, pp.415-442, 1960-06-15

著者

黒瀬 築 柳原 俊太郎 宮田 一司 濱本 芳徳 森 英夫

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.17-00593, 2018 (Released:2018-06-25)

参考文献数

13

被引用文献数

1

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For the development of industrial heat pump system supplying a high-temperature heat source, the application of chevron type plate heat exchanger is being considered. In the present study, experiments and numerical simulation on flow characteristics in single chevron channel with chevron angle 30°, 45° and 65° were respectively performed. In the experiment, the pressure drop of the whole chevron channel and local pressure drops in each chevron channel were measured and path lines were also observed. Besides, numerical simulation reproduced the experimental results well. From both of the experimental and simulation results, it was confirmed that the pressure drop of the chevron channel became larger with increasing the chevron angle due to the strong mixing of fluids in the respective furrows of adjacent chevron plates especially in the high chevron angle channel. In such the high chevron angle channel, velocity and pressure drop gradient distributions were almost uniform in the channel width direction normal to main flow. While, in the small chevron angle channel, the fluids mixing between furrows of adjacent plates was weak and the velocity and pressure drop gradient distributions were markedly large in the width direction. Furthermore, it was found that large pressure drops occurred in the inlet and outlet regions where the channel had flow width expansion and contraction, respectively. The large pressure drops in the inlet and outlet regions affected the overall pressure drop in the chevron channel, especially in the low chevron angle channel. For each chevron angle channel, the local friction factor was obtained and the loss coefficient for the flow expansion and contraction at inlet and outlet regions was determined. Based on these results, the prediction method of overall pressure drop in the chevron channel was proposed.

著者

宮田 一司 森 英夫 谷口 隆寛 梅沢 修一 杉田 勝彦

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.855, pp.17-00280-17-00280, 2017 (Released:2017-11-25)

参考文献数

15

被引用文献数

2

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For the development of industrial heat pump systems supplying high-temperature heat source over 130 °C, experiments were carried out on cooling heat transfer of supercritical pressure HFO1234ze(E) flowing in a plate-type heat exchanger (PHE). HFO1234ze(E) with low Global Warming Potential (GWP) is expected as an alternative to refrigerant HFC134a. In the experiment, heat transfer coefficient data were obtained at different pressures including a near-critical pressure condition. To obtain the heat transfer coefficient, an integral method was used for evaluating the mean temperature difference between the refrigerant and cooling water in the PHE. Based on the measurements, characteristics of cooling heat transfer of supercritical pressure HFO1234ze(E) in the PHE were clarified. Generally, heat transfer coefficient showed considerably large values compared with tube flow, attributed to strong turbulence or agitation promoted by corrugated geometry of the PHE plate, and reached a maximum in the vicinity of the pseudocritical point. As the pressure approached the critical pressure, the peak of heat transfer coefficient became higher at lower bulk enthalpy, reflecting the pressure dependence of isobaric specific heat of the refrigerant. These results mean, even in the pseudocritical region where strong temperature dependency of physical properties appears, properties change in the flow cross section was small compared to the tube flow, although not negligible. The correlation developed in the previous study overestimated the measured heat transfer coefficient in the pseudocritical region for the pressure of the reduced pressure 1.01 very close to the critical pressure and also in the enthalpy region near to and lower than the pseudocritical point for the pressures of the reduced pressure about 1.1 or higher. For the better prediction, the necessity to consider the small but non-negligible properties change in the flow channel cross section was recognized.

著者

榎木 光治 宮田 一司 森 英夫

出版者

公益社団法人 日本冷凍空調学会

雑誌

日本冷凍空調学会論文集 (ISSN:13444905)

巻号頁・発行日

vol.32, no.3, pp.275-283, 2015-09-30 (Released:2016-09-30)

参考文献数

23

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著者らは,先に,微細円形流路内の沸騰熱伝達率について,強制対流蒸発と核沸騰の寄与に加え,新たに微細流路に特有の液膜熱伝導蒸発の寄与を考慮した精度の高い整理式を提案した.液膜熱伝導蒸発は,主にスラグ流における気体プラグ周囲の薄液膜を通した熱伝導による蒸発熱伝達である.しかしながら,近年広く用いられる比較的高圧の冷媒に対して整理式で用いた核沸騰整理式の予測精度が良くないこと,また,最近得た水平流の低流量のデータに対して整理式の予測精度が低いことが明らかになった.本研究では,この2 点について以前に提案した整理式を修正し,予測精度の改善を行った.新たに得られた整理式は,著者らのR 410A のデータのみならず,他研究者によるR 32,R 1234yf およびH2O やCO2 を含む広範囲のデータに対して,水平流の低流量の条件を含め,高い予測精度を示した.